1. Field of the Invention
This invention relates to a metalurgy, and more particularly to iron and steel recovery from scrap metal.
2. Description of the Prior Art
Derelict or abandoned automobiles whose whole or parts are rendered useless are causing a major disposal problem. While various recycling methods are known for most metal parts of the automobile, heretofore, no safe method has yet been devised to recycle a used automobile gas tank for its metal value. Also, there is no known method to also recover volatile hydrocarbons which are contained within the tank shell. The conventional method of gas tank disposal is merely to bury the abandoned tank, thereby rendering the used gas tank a complete loss or waste.
Some prior art is known. Rhinehart, in U.S. Pat. No. 4,014,681, discloses an energy recycling process to be used with automobile scrap. In the Rhinehart process, a totally stripped vehicle body--that is, one stripped of alternators, radiators, generators, starters, voltage regulators, transmissions, carburetors, glass, etc.--is moved by conveyor into a more or less open cupola where it is melted. Carbon electrodes are required to generate the necessary 3,200 degree F. temperature. The thrust of this patent is the use of heat generated in recycling to, for example, preheat the charge. The charge is drawn off molten, in layers if possible. All hot gases are removed as exhaust and discharged into the atmosphere.
Evans et al, in U.S. Pat. No. 4,200,262, discloses a method and apparatus for removing combustible material from metal scrap. Evans characterizes his apparatus as a rotating retort and its use is for burning combustibles such as oil from scrap metal such as turnings, chips, shearings, punchings, and other similar materials which tend to include a coating of oil which must be removed before reclaiming. In the Evans apparatus, temperatures of 50 to 500 degrees F. are used in an oxidizing atmosphere through which the material moves, conveyed forward by the rotating retort. Evans uses a flame to burn the combustibles that are not recovered.
None of these references deal with a high alloy scrap which removes the alloys in a nonmolten atmosphere. Many prior art solutions are totally noneconomical because of high energy demands of the process as would be needed for the high temperatures utilized in, for example, Rhinehart. Furthermore, none of these references address themselves to the recycling or recovery of an automobile gas tank and its residual volatile hydrocarbons.